Conventional wisdom tells us that the best way to safeguard online accounts is to set strong passwords and change them regularly. But all that really provides is a false sense of confidence, because data thieves almost never go after individuals. Why bother trying to hack one account when you can steal thousands of them - passwords included - in a system data breach?

Thefts of user databases seem to be happening with increasing frequency, and just last week, we learned that a Russian gang stole more than a billion user IDs and passwords and 500 million e-mail addresses from more than 400,000 websites. (That sounds preposterous, but, hey, it must be true because the New York Times reported it.)

Anyway, you definitely should change the password of an account you know has been harvested in a system data breach - hopefully before the thieves have time to exploit or sell your information. But regularly changing passwords won't make your accounts any more secure, because the odds of having account information stolen in a data breach have nothing to do with how long you've had your password.

Security experts are correct when they say that strong passwords, consisting of random numerals, letters and symbols, make accounts a lot harder to hack. But guess what? That's one reason data thieves breach systems and steal accounts wholesale.

Of course, you should have different passwords for all your accounts, so that the theft of one doesn't compromise the others. And you might as well make the passwords strong, which is just as easy as creating weak ones. A good password manager like Dashlane or LastPass can do it for you, and you can use the manager to log into your accounts, eliminating the need to remember passwords or user IDs.

Q:I'm looking to get a streaming media device, and I was wondering which one you would recommend among the plethora of options, including Roku, Apple TV, Chromecast and Amazon Fire TV.

A: Well, I'd rule out Chromecast because it doesn't come with a remote control. Instead, you must use an Android phone or tablet with an app. That's lame.

I'd also eschew the Apple TV. There's nothing inherently wrong with it, but the current model is showing its age. It lacks the ability to search across multiple channels, it doesn't offer Amazon Instant Video (or Amazon Prime), and it doesn't have any gaming capabilities. And the next version of Apple TV may not come out until 2015.

That leaves Amazon Fire TV and Roku. The Amazon device, which was released in April, has been adding content and closing the gap, but Roku still has a much larger channel library. Both devices offer multichannel search; Text searching is easier on the Roku, but the Amazon Fire TV lets you search with your voice - a feature that could become a big advantage as soon as Amazon incorporates more channels into the search system, including Netflix.

The biggest drawback of the Amazon Fire TV is that its user interface favors content from Amazon - much like the company's tablets and new smartphone. So right now, I would say the Roku 3 is the best of the bunch. It's slick, easy to use and packed with content. By the way, the Amazon, Roku and Apple devices all list for about $100.

Q:Thanks for tipping us off that Comcast had doubled Internet speeds on its most popular plans in California. The day after your column item appeared, I got an e-mail from Comcast announcing the increase on my Xfinity Performance Internet service from 25 to 50 megabits per second. I'm not seeing a noticeable difference in Internet surfing or streaming video, but my Wi-Fi signal is stronger. Do you think the speed boost has something to do with the fact that Comcast is turning users' homes into public hotspots?

A: It might. For anyone who still doesn't know, new home-networking equipment installed by Comcast supports a second Wi-Fi network that can be accessed by other Xfinity customers for free (or by anyone else for a fee). By the end of this year, Comcast plans to have some 8 million such hotspots around the country.

By increasing Internet speeds, Comcast strengthened its Wi-Fi signals for both home networks and the Xfinity hotspots.

You can disable the hotspot if you want to. Or, like me, you can use your own modem and router. That way, you don't have to pay a monthly equipment fee, and Comcast doesn't get to use your home as a hotspot. Win-win.